[b][i]Hopefully someone can help with this as I am getting worried more and more about it. Getting a little stressful as I think it is affecting my family's health but cannot be sure this is the reason.[/i][/b] :-(

[b]Problem:[/b]
Wall paper coming off, 1ft square, pale yellowy brown stain, and small white what I can only describe as nodules about 2mm across and sticking out by 1 to 2mm, failing plaster (distintergrating / powdering away when prodded).
This is on the first 18" inches or thereabouts above the skirting board. It is mostly around the chimney breast downstairs which is on a party wall but it does extend "slightly" over the wall to about 1.5m from the chimney breast through a 90 deg bend to the next wall.
The room smells very musty also.
I don't know if it is a co-incidence but we all seem to get a very sore throat, upper chest infections / cough, and sore eyes whenever we are in this room (which is the biggest one of two reception rooms and our main living space) for longer than a couple of hours.

[b]House Details:[/b]
We moved here 4 years ago.
3 bedroom semi detached built around 1930s with a suspended wooden floor with almost two foot gap of cavity with soil and rubble as the base.
Chimney has a gas fire we use very rarely at the base.
GCH from a combi boiler under the stairs (again a fair distance away in a separate room) is on all the time at a steady 21deg C except in summer.
UPVC double glazed and all windows in house are on the latch thus always venting.
We have cavity wall insulation - installed by previous owners.
We have at least 3 airbricks (which are clear and obstruction free through to the cavity) per external wall.
Chimney pots have a type of cap on - I don't know what they are called - but it is a half pipe cap to keep the rain out but still allow the fire to vent. When the gas fire is on it does suck up quite well so it works.

[b]Own Investigations:[/b]
>>> There aren't any water pipes any where near the area unless they are under next doors on the other side of the part wall.
>>> Cavity under floor boards at the other end of the same room seems to have a draft as expected and the soil / rumble is just like, well, soil really. Not dry and not squidgy either. But, it is like that all over under the floorboards.
>>> The area on the wall affected feels very very cold to touch. I don't know what the temperature is but it is very much colder than any other wall area at the same level.
>>> There is no visible sign of condensation.

[i][b]Help, thoughts, things to try desperately needed.[/b][/i] :-(

Need to know the Cause and Solution plus whether these things can affect our health or whether it is my imagination and a matter of having a germ magnet child at nursery.

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